Image display device, the image display system, and image display method

ABSTRACT

An image display device having a display panel, the device being utilized to form an image display system in which a plurality of the image display devices are arrayed in one or both of vertical and horizontal directions to display one image as a whole while an image allocated to each device is displayed via the corresponding display panel, the image display device includes a reading processing unit that reads out image information and delays start of output of this image information by a predetermined period of time determined based on the number of the image display devices which forms the image display system and a row to which the present device belongs in the vertical arrangement.

TECHNICAL FIELD

The present invention relates to an image display device, an imagedisplay system, and an image display method, which are utilized formulti-display technology.

BACKGROUND ART

An example of electronic advertisement bulletin boards provided onbuildings or the like utilizes a (multi-display or multi-monitor)technique in which a plurality of display panels (i.e., displays) arearrayed in one or both of the vertical and horizontal directions so asto display one image (as a whole) on the whole of the displays and thusimplement a large screen.

In an image display system utilizing the above multi-display technique,the whole of the individual display panels display one image. Therefore,when each display panel employs an ordinary display device, a displayshift of one frame may be produced between upper and lower (adjacent)display panels. More specifically, each display panel displays an imageby scanning each frame in the horizontal direction while simultaneouslyscanning the frame in the vertical direction. For example, it is assumedthat each display panel has n lines (horizontal lines). In this case,the display panel performs the relevant drawing process from the firstline (the top of the display panel) to the last n-th line (the bottom ofthe display panel) to complete the display of the target image. In orderto display a video, based on image information items input at everymoment, the display panel repeats the above scanning process in thehorizontal and vertical directions, for each of different images.

FIG. 6A is a diagram utilized to explain a display shift produced in animage display system related to an embodiment of the present invention.FIG. 6B is a diagram utilized to show an example of displayed images inindividual frames.

In FIG. 6A, time is shown along the horizontal axis and the verticalaxis corresponds to the vertical direction of each display panel, bywhich transition in the display image in each display panel is shown.FIG. 6B shows display images of (N−1)th, N-th, and (N+1)th frames.

In the following case, in an image display system utilizing amulti-display in which display panels are arrayed in one or both of thevertical and horizontal directions, the scanning in the verticaldirection is synchronously performed between all display panels. In thiscase, at the moment next to the completion (at time T1) of the drawingof the n-th line where the (N−1)th image is displayed on the entirescreen, the individual display panels simultaneously start the drawingof the first line of a different image (i.e., image N) (see FIG. 6A).Then, of any two vertically adjacent display panels, the upper displaypanel still displays the n-th line of the (N−1)th image while the firstline of the lower display panel already displays the N-th image. In theimage display system using a multi-display, ideally, all display panelsdisplay the same image. However, in the above-described display device,a display shift of one frame is always produced at the boundary betweenthe upper and lower adjacent display panels.

Patent Document 1 displays a technique in which of any two verticallyadjacent display panels, the start time of the vertical scanning of thelower display panel is delayed by one frame. According to thistechnique, it is possible to cancel a display shift of one frameproduced at the boundary between the upper and lower adjacent displaypanels.

PRIOR ART DOCUMENT Patent Document

-   Patent Document 1: Japanese Unexamined Patent Application, First    Publication No. 2001-222269.

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

FIG. 7A is a diagram utilized to explain display shift correction meansin an image display system related to an embodiment of the presentinvention. FIG. 7B is a diagram utilized to show an example of displayedimages in individual frames.

Similar to FIGS. 6A and 6B, FIGS. 7A and 7B respectively show thetransition in the display image in each display panel and the displayimages of (N−1)th, N-th, and (N+1)th frames. As described above, in theimage display system described in Patent Document 1, the start time ofthe vertical scanning of the lower display panel is delayed by oneframe. Accordingly, as shown in FIG. 7A, the same image is alwaysdisplayed at the boundary between the upper and lower display panels.

According to the means of Patent Document 1, an image display systemconsists of only two upper and lower panels can be handled by producingonly one-frame delay. However, in an image display system consists ofthree or more display panels arranged vertically, time required to thecompletion of the drawing is delayed by the number of framescorresponding to the number of the vertically arranged display panels(see FIG. 7A). In this case, the time from the start to the completionof the drawing of one image (as a whole) over all of the display panelsincreases. Accordingly, if a sudden screen switching or the like occurs,then visually, the switching of the image displayed at the lower side isdelayed.

The present invention provides an image display device, an image displaysystem, and an image display method.

Means for Solving the Problem

As a first mode of the present invention, an image display device has adisplay panel, the device being utilized to form an image display systemin which a plurality of the image display devices are arrayed in one orboth of vertical and horizontal directions to display one image as awhole while an image allocated to each device is displayed via thecorresponding display panel. The image display device includes:

a reading processing unit that reads out image information and delaysstart of output of this image information by a predetermined period oftime determined based on the number of the image display devices whichforms the image display system and a row to which the present devicebelongs in the vertical arrangement.

As a second mode of the present invention, an image display system, inwhich a plurality of the image display devices are arrayed in one orboth of vertical and horizontal directions to display one image as awhole while an image allocated to each device is displayed via thecorresponding display panel, includes:

each of the image display devices has a reading processing unit thatreads out image information and delays start of output of this imageinformation by a predetermined period of time determined based on thenumber of the image display devices and a row to which the presentdevice belongs in the vertical arrangement.

As a third mode of the present invention, in an image display method inwhich a plurality of the image display devices are arrayed in one orboth of vertical and horizontal directions to display one image as awhole while an image allocated to each device is displayed via thecorresponding display panel:

a reading processing unit provided in each of the image display devicesreads out image information and delays start of output of this imageinformation by a predetermined period of time determined based on thenumber of the image display devices and a row to which the presentdevice belongs in the vertical arrangement.

Effect of the Invention

According to the above-described image display device, the image displaysystem, and the image display method, no considerable delay is generatedin the operation of displaying one image, and it is possible to reduce adisplay shift produced at the boundary between the display panels.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a functional configuration of an imageinformation processing device according to an embodiment of the presentinvention.

FIG. 2 is a diagram showing a functional configuration of an imagedisplay system according to an embodiment of the present invention.

FIG. 3 is a diagram showing a timing chart of the vertical synchronizingsignal generated by the reading processing unit according to anembodiment of the present invention.

FIG. 4A is a first diagram utilized to explain an effect based on theoperation of the image information processing device according to anembodiment of the present invention.

FIG. 4B is a diagram utilized to show an example of displayed images inindividual frames.

FIG. 5 is a second diagram utilized to explain an effect based on theoperation of the image information processing device according to anembodiment of the present invention.

FIG. 6A is a diagram utilized to explain a display shift produced in animage display system related to the present invention.

FIG. 6B is a diagram utilized to show an example of displayed images inindividual frames.

FIG. 7A is a diagram utilized to explain display shift correction meansin an image display system related to the present invention.

FIG. 7B is a diagram utilized to show an example of displayed images inindividual frames.

MODE FOR CARRYING OUT THE INVENTION

Below, an embodiment of the present invention will be explained withreference to the drawings.

FIG. 1 is a diagram showing a functional configuration of an imageinformation processing device according to an embodiment of the presentinvention.

An image information processing device 1 pertaining to the presentembodiment has a writing processing unit 10, an image informationstorage unit 11, and a reading processing unit 12.

FIG. 2 is a diagram showing a functional configuration of an imagedisplay system according to an embodiment of the present invention.

As shown in FIG. 2, an image display system 100 has a plurality of imagedisplay devices 5, each including the image information processingdevice 1, an information input unit 2, a drive unit 3, and a displaypanel 4. Here, although FIG. 2 shows only one image display device 5,the image display system 100 actually includes the plurality of theimage display devices 5.

The image display devices 5, each including the image informationprocessing device 1, the information input unit 2, the drive unit 3, andthe display panel 4, display images allocated to the individual imagedisplay devices 5 via the display panels 4 provided therein. Such imagedisplay devices 5 are arrayed in one or both of the vertical andhorizontal directions so as to form the image display system 100 whichdisplays one image as a whole.

Here, the image information processing device 1 stores information, inadvance in a storage unit (not shown), about a position to which theimage display device 5 provided with this image information processingdevice 1 belongs. For example, when the image display system 100 isformed by arranging three image display devices 5 both in the verticaland horizontal directions, the image information processing device 1stores arrangement information of the image display devices 5 (it may berepresented by X and Y coordinates, where X and Y each have a value of 1to 3).

Based on the arrangement information, the image information processingdevice 1 applies a predetermined process to image information input tothe corresponding image display device 5 and outputs the imageinformation (to which the predetermined process has been applied) to thedisplay panel 4 of the relevant image display device 5.

In the explanation below, the above condition such that the imagedisplay system 100 is formed by arranging three image display devices 5both in the vertical and horizontal directions is employed. However, thepresent embodiment is not limited to such an arrangement.

Next, each functional unit will be explained.

The writing processing unit 10 is a functional unit to receive imageinformation from an external device at every moment and store receivedindividual information items serially in the image information storageunit 11. For example, the writing processing unit 10 generates a writingclock signal obtained by multiplying a horizontal synchronizing signalto have an integral multiple thereof, where the horizontal synchronizingsignal is input together with the image information. Although thisgeneration process of the writing clock signal performed in the writingprocessing unit 10 is performed spontaneously by the writing processingunit 10, it may be performed in accordance with an instruction from acontrol unit (not shown) provided separately in the image informationprocessing device 1. In addition, the above image information is imageinformation utilized to display a complete (one) image as a whole by theentire image display system 100. Therefore, the image information isinput, in common, into each of the image information processing devices1 which belongs to the corresponding image display device 5.

The image information storage unit 11 has an area utilized totemporarily store the image information input into the writingprocessing unit 10. The image information storage unit 11 ischaracterized by having an memory area capable of storing imageinformation of one frame and also image information of at least oneline. This image information storage unit 11 is generally a storagedevice called a “video memory”.

Based on a predetermined vertical synchronizing signal, the readingprocessing unit 12 is a functional unit which outputs partial imageinformation allocated to the own device (i.e., the present image displaydevice 5 of this reading processing unit 12) in the image informationstored in the image information storage unit 11, to the display panel 4at every moment. That is, the reading processing unit 12 reads out thepartial image information, which is a region allocated to the own device(the image display device 5) in the image information stored in theimage information storage unit 11, and outputs the read information tothe display panel 4. In this process, the reading processing unit 12refers to the arrangement information which is stored by the imageinformation processing device 1 in advance. For example, in case of theimage information processing device 1 of the image display device 5located at the upper left corner of the image display system 100 (thelocation may be represented by “X =1 and Y=1”), the reading processingunit 12 reads out, in the image information stored in the imageinformation storage unit 11, (information of) a region corresponding tothe upper left ⅓ of an image to be displayed based on the relevant imageinformation. Furthermore, the reading processing unit 12 outputs therelevant image information by processing the above upper left ⅓ regionso as to be displayed as a triple-enlarged image on the display panel 4.Such a process is performed by the image information processing device 1of each of the image display devices 5 and thus one enlarged image isdisplayed by the nine image display devices 5 in the image displaysystem 100.

The information input unit 2 is a functional unit utilized to receivethe image information input from an external device, which may be avideo recorder, a video playback device, or the like. If the input imageinformation is an analog signal, the information input unit 2 may beprovided with an A/D converter.

The drive unit 3 is a functional unit utilized to perform an electricprocess of actually displaying a predetermined image on the displaypanel 4 based on an electrical signal of the image information inputfrom the image information processing device 1. For a typical TFT (ThinFilm Transistor) liquid crystal panel, such a functional unit is anelectric circuit element called a “gate driver”, a “source driver”, orthe like.

The display panel 4 is a functional unit utilized to display, accordingto the above electric process of the drive unit 3 based on the imageinformation, an image based on the relevant image information in amanner visible to users. More specifically, the display panel 4 may be aliquid crystal display panel, an organic EL display panel, a plasmadisplay panel, or the like. In addition, the image display system 100implements a large screen by arraying a plurality of the image displaydevices 5, each including the display panel 4, in one or both of thevertical and horizontal directions.

FIG. 3 is a diagram showing a timing chart of the vertical synchronizingsignal generated by the reading processing unit according to anembodiment of the present invention.

Here, a specific process performed by the reading processing unit 12according to the present embodiment will be described with reference toFIG. 3. First, the reading processing unit 12 receives a first verticalsynchronizing signal. The first vertical synchronizing signal is acommon signal input into each of the image information processingdevices 1, and a reference signal utilized by the display panels 4 todisplay one image as a whole. As shown in FIG. 3, the first verticalsynchronizing signal is a signal that outputs a negative pulse signalfor each frame. Based on the timing decided by the negative pulses, thereading processing unit 12 starts the output of the image information.

At the pulse intervals of the first vertical synchronizing signal, thewriting processing unit 10 writes the image information of one image inthe image information storage unit 11 sequentially.

In the present embodiment, “frame” is a unit of the image information,utilized to display one image (from the first line to the n-th linethereof) by one display panel.

The reading processing unit 12 in the present embodiment ischaracterized by delaying the start of the signal output to the displaypanel 4 by a predetermined period of time determined based on the number(N) of the image display devices 5 arranged vertically. Below, aspecific processing thereof will be explained.

First, when the reading processing unit 12 receives the first verticalsynchronizing signal, the reading processing unit 12 refers to theposition (X and Y) of the display panel 4 of the present device and thevertical arrangement number N which denotes the number of the imagedisplay devices 5 arranged vertically in the image display system 100.Here, the image information processing device 1 of each of the imagedisplay devices 5 which form the image display system 100 stores thevertical arrangement number N in a predetermined storage unit (notshown) in advance. Since the image display system 100 explained in thepresent embodiment is a system in which three image display devices 5are arrayed in each of the vertical and horizontal directions, thevertical arrangement number N is 3.

The reading processing unit 12 also delays the start of the signaloutput to the display panel 4 by a predetermined period of timedetermined based on the row (i-th row), in the vertical arrangement(number N), to which (the i-th row) the own device (the image displaydevice 5) belongs. In the following explanation, among the image displaydevices 5 which form the image display system 100 in the presentembodiment, the image display devices 5 which belong to the top row arerepresented as belonging to “the first row”, the image display devices 5which belong to the middle row are represented as belonging to “thesecond row”, and the image display devices 5 which belong to the bottomrow are represented as belonging to “the third row”.

First, the reading processing unit 12 refers to the vertical arrangementnumber N and the coordinate information of its own device (the imagedisplay device 5) to determine which row the own device belongs to.After the reading processing unit 12 identifies the vertical arrangementnumber (N) and the row (i) to which the relevant display panel 4belongs, a delay amount Td is computed based on the following formula.Here, “V” in Formula (1) is a unit time length required to display animage per unit frame on one display panel 4 (i.e., “1V” equals a timelength required to display an image of one frame).

$\begin{matrix}{\lbrack {{Formula}\mspace{14mu} 1} \rbrack\mspace{625mu}} & \; \\{{Td} = {\frac{i - 1}{N - 1}V}} & (1)\end{matrix}$

According to Formula (1), the reading processing unit 12 computes secondvertical synchronizing signals as explained below. Since the delayamount Td is 0 when the own device (the image display device 5) belongsto the first row, the corresponding reading processing unit 12 directlyuses the received first vertical synchronizing signal as the secondvertical synchronizing signal without performing any process for thefirst vertical synchronizing signal (see FIG. 3). Since the delay amountTd is ½V (i.e., (½)V) when the own device belongs to the second row, thecorresponding reading processing unit 12 applies a delay shift of ½V tothe first vertical synchronizing signal and uses the delayed signal asthe second vertical synchronizing signal (see FIG. 3). Additionally,since the delay amount Td is 1V when the own device belongs to the thirdrow, the corresponding reading processing unit 12 applies a delay shiftof 1V to the first vertical synchronizing signal and uses the delayedsignal as the second vertical synchronizing signal (see FIG. 3).

The reading processing units 12 of the image display devices 5 arrangedin the first row each read out partial image information (for the firstrow) allocated to each device from the image information storage unit 11and outputs the relevant partial image information from time T0 to timeT1 (i.e., after 1V), by performing no delay operation. In this process,the reading processing unit 12 displays an image based on the partialimage information in a triple-enlarged manner

The reading processing units 12 of the image display devices 5 arrangedin the second row each read out partial image information (for thesecond row) allocated to each device from the image information storageunit 11 and outputs the relevant partial image information from time T01to time T11 (i.e., after 1V), by applying a delay of ½V to time T0. Inthis process, the reading processing unit 12 also displays an imagebased on the partial image information in a triple-enlarged manner

Similarly, the reading processing units 12 of the image display devices5 arranged in the third row each read out partial image information (forthe third row) allocated to each device from the image informationstorage unit 11 and outputs the relevant partial image information fromtime T1 to time T2 (i.e., after 1V), by applying a delay of 1V to timeT0. In this process, the reading processing unit 12 also displays animage based on the partial image information in a triple-enlarged manner

FIG. 4A is a first diagram utilized to explain an effect based on theoperation of the image information processing device according to anembodiment of the present invention. FIG. 4B is a diagram utilized toshow an example of displayed images in individual frames.

Similar to FIGS. 6A and 6B or FIGS. 7A and 7B, FIGS. 4A and 4Brespectively show a transition in the image displayed in the imagedisplay devices 5 and display images of (N−1)th, N-th, and (N+1)thframes. For example, FIG. 4A shows that the first line of each displaypanel in the first row starts display of image N−1 (i.e., the (N−1)thimage) from time T0 and the displayed image is switched to image N attime T1. FIG. 4A also shows that the n-th line of the display panel 4 ofeach image display device 5 in the first row starts display of image N−1from time T1 and the displayed image is switched to image N at time T2.

In addition, as shown in FIG. 4A, the first line of the display panel 4of each image display device 5 in the second row starts display of imageN−1 from time T01 and the displayed image is switched to image N at timeT11. Additionally, the n-th line of the display panel 4 of the imagedisplay device 5 in the second row starts display of image N−1 from timeT11 and the displayed image is switched to image N at time T21.

Furthermore, the first line of the display panel 4 of each image displaydevice 5 in the third row starts display of image N−1 from time T1 andthe displayed image is switched to image N at time T2. Additionally, then-th line of the display panel 4 of the image display device 5 in thethird row starts display of image N−1 from time T2 and the displayedimage is switched to image N at time T3.

As described above, according to the operation of the image informationprocessing device 1 in the present embodiment, display of each imagedisplay device 5 in the first row is started at time T0. That is, forimage N−1, the display panel 4 of each image display device 5 located inthe first row starts the display of the first line at T0, sequentiallyadvances the relevant drawing within the time length 1V, and completesthe drawing of the n-th line at time T1. At this time T1, the displaypanel 4 of each image display device 5 in the first row completes theimage N−1.

In contrast, for image N−1, the display panel 4 of each image displaydevice 5 located in the second row starts the display of the first lineat T01 when ½V has just elapsed from time T0 (see FIG. 4A). At this timeT01, the display panel 4 of each image display device 5 located in thefirst row has completed the drawing of only the upper half of image N−1.The display panel 4 of each image display device 5 in the second rowsequentially advances the relevant drawing within the time length 1Vmeasured from time T01, and completes the drawing of the n-th line attime T11. In this process in the second row, since the display panel 4of each image display device 5 located in the first row starts thedrawing of the next image N from time T1, the image of the n-th line ofthe display panel 4 of each image display device 5 in the first rowcoincides with the image of the first line of the display panel 4 ofeach image display device 5 in the second row within a time length of ½Vfrom time T1 to time T11.

In addition, for image N−1, the display panel 4 of each image displaydevice 5 located in the third row starts the display of the first lineat T1 when 1V has just elapsed from time T0 (see FIG. 4A). At this timeT1, the display panel 4 of each image display device 5 located in thefirst row has completed the drawing of the entire image N−1, and thedisplay panel 4 of each image display device 5 located in the second rowhas completed the drawing of only the upper half of image N−1. Thedisplay panel 4 of each image display device 5 in the third rowsequentially advances the relevant drawing within the time length 1Vmeasured from time T1, and completes the drawing of the n-th line attime T2. In this process in the third row, since the display panel 4 ofeach image display device 5 located in the second row starts the drawingof the next image N from time T11, the image of the n-th line of thedisplay panel 4 of each image display device 5 in the second rowcoincides with the image of the first line of the display panel 4 ofeach image display device 5 in the third row within a time length of ½Vfrom time T11 to time T2.

According to the display operation of an image by the image informationprocessing device 1, no delay of one frame or greater is producedbetween the image displayed by the image display devices 5 located inthe first row and the image displayed by the image display devices 5located in the third row. In addition, the image information processingdevice 1 can perform the image display while generating a time length ½Vduring which the same image is displayed at the boundary between theupper and lower adjacent display panels.

Therefore, according to the image information processing device 1 of thepresent embodiment, no considerable delay is generated in the operationof displaying one image, and it is possible to reduce a display shiftproduced at the boundary between the display panels.

In order to implement the above operation, the image information storageunit 11 has an memory area capable of storing image information of oneframe and further image information of at least one line.

The writing processing unit 10 writes the image information of one framein the image information storage unit 11 sequentially at every moment,based on the first vertical synchronizing signal. That is, in FIG. 4A,the writing processing unit 10 writes the image information, from imageinformation corresponding to the first line to the image informationcorresponding to the n-th line, within a time length from time T0 totime T1. In the next time length (from time T1 to time T2), differentimage information (N) is overwritten on the image information storageunit 11. Accordingly, the writing processing unit 10 overwrites theimage information utilized to the drawing of the next image sequentiallyfor each frame, based on the first vertical synchronizing signal.

Here, the start of overwriting of the image information of image N ontothe image information of image N−1 starts at time T1. Therefore, in thedisplay panel 4 of each image display device 5 located in the first row,the partial image information for the upper ⅓ of image N−1 is present inthe image information storage unit 11 during a time length from time T0to time T1 (during which this partial image information is to bedisplayed in the relevant display panel 3) without being overwrittenwith the next image information (of image N). Accordingly, each imagedisplay device 5 located in the first row can advance the drawingoperation by using the image information storage unit 11 sequentially atevery moment, based on the first vertical synchronizing signal withoutproblems.

Additionally, at time T11, in the upper half of the image informationstorage unit 11, the partial image information for each image displaydevice 5 located in the second row (i.e., partial image information forthe middle ⅓ of image N−1) has already been overwritten with the imageinformation for the next image (i.e., image N). However, at this time(T11), since the display of the present partial image information hascompleted, the drawing operation can be advanced without problems.

For the partial image information for each image display device 5located in the third row (i.e., partial image information for the lower⅓ of image N−1), at time T2 when the n-th line of the display panel 4should be displayed, the image information corresponding to the bottomline in the image information of image N−1 stored in the imageinformation storage unit 11 is overwritten with the image information ofimage N. Therefore, in order to display the image information, whichcorresponds to the bottom line in the image information of image N−1, inthe n-th line of each display panel 4 of the third row at time T2, it isnecessary to store, in advance, the image information for the n-th lineof image N−1, separately in a memory area provided as a reserve.Accordingly, in addition to the memory area utilized to store imageinformation of one frame, the image information storage unit 11 also hasa memory area utilized to store at least one line.

FIG. 5 is a second diagram utilized to explain an effect based on theoperation of the image information processing device according to anembodiment of the present invention. FIG. 5 shows a transition in thedisplay of each image display device 5 in a case in which four imagedisplay devices 5 are arrayed vertically (i.e., N=4). When the verticalarrangement number N is 4, according to Formula (1), the readingprocessing unit 12 of each image display device 5 determines that adelay amount of ⅓V is assigned to the display panels 4 in the secondrow, a delay amount of ⅔V is assigned to the display panels 4 in thethird row, and a delay amount of 1V is assigned to the display panels 4in the fourth row.

In this case, for image N−1, the display panel 4 of each image displaydevice 5 in the second row starts the drawing of the first line at timeT01 when ⅓V has just elapsed from time T0 (see FIG. 5). The displaypanel 4 of each image display device 5 in the second row sequentiallyadvances the relevant drawing within the time length 1V measured fromtime T01, and completes the drawing of the n-th line at time T11. Inthis process, within a time length of ⅓V from time T1 to time T11, theimage of the n-th line of the display panel 4 of each image displaydevice 5 in the first row coincides with the image of the first line ofthe display panel 4 of each image display device 5 in the second row.

Similarly, for image N−1, the display panel 4 of each image displaydevice 5 in the third row starts the drawing of the first line at timeT02 when ⅔V has just elapsed from time T0 (see FIG. 5). The displaypanel 4 of each image display device 5 in the third row sequentiallyadvances the relevant drawing within the time length 1V measured fromtime T02, and completes the drawing of the n-th line at time T12. Inthis process, within a time length of ⅓V from time T11 to time T12, theimage of the n-th line of the display panel 4 of each image displaydevice 5 in the second row coincides with the image of the first line ofthe display panel 4 of each image display device 5 in the third row.

For the display panel 4 of each image display device 5 in the third rowand the display panel 4 of each image display device 5 in the fourthrow, similarly, within a time length of ⅓V from time T12 to time T2, theimage of the n-th line of the display panel 4 of each image displaydevice 5 in the third row coincides with the image of the first line ofthe display panel 4 of each image display device 5 in the fourth row.

As described above, according to the operation of the image informationprocessing device 1, even when the vertical arrangement number N is 4,no delay of one frame or greater is produced between the image displayedby the image display devices 5 located in the first row and the imagedisplayed by the image display devices 5 located in the fourth row. Inaddition, the image information processing device 1 can perform theimage display while generating a time length ⅓V during which the sameimage is displayed at the boundary between the upper and lower adjacentdisplay panels.

The above-described image display system 100 includes a computer system.The individual steps in the operation of the image display system 100are stored as a program in a computer-readable storage medium, and theoperation is performed when the relevant computer loads and executes theprogram. The above computer readable storage medium is a magnetic disk,magneto optical disk, CD-ROM, DVD-ROM, semiconductor memory, or thelike. In addition, the relevant computer program may be provided to acomputer via a communication line, and the computer which received theprogram may execute the program.

In addition, the image display system 100 according to an embodiment hasa mode in which a plurality of image display devices 5, each includingthe image information processing device 1 and the display panel 4, bywhich the image information processing device 1 is assigned with eachdisplay panel 4. However, this mode is not limited in other embodiments.For example, the image display system 100 may have a form in which aplurality of display panels 4 and one image information processingdevice 1 are provided. In this case, the relevant image informationprocessing device 1 may have an image information distribution unit thatdistributes image information items distributed and output to theindividual display panels 4.

Additionally, the above embodiments have been shows as examples and itis not intended to limit the scope of the invention. These embodimentsare capable of being implemented in other various forms, and variousomissions, replacement, or variations can be performed without departingfrom the scope of the invention. These embodiments and theirmodifications fall within the scope and concept of the invention and areincluded in the scope of the invention shown in the claims and itsequivalents.

INDUSTRIAL APPLICABILITY

No considerable delay is generated in the operation of displaying oneimage, and it is possible to reduce a display shift produced at theboundary between the display panels.

REFERENCE SYMBOLS

-   1 image information processing device-   10 writing processing unit-   11 image information storage unit-   12 reading processing unit-   2 information input unit-   3 drive unit-   4 display panel-   5 image display device-   100 image display system

The invention claimed is:
 1. An image display device having a displaypanel, the device being utilized to form an image display system inwhich a plurality of image display devices are arrayed in a verticaldirection to display one image as a whole while an image allocated toeach device is displayed via the corresponding display panel, the imagedisplay device comprising: a reading processing unit that reads outpartial image information of a frame and delays a start of an output ofthe partial image information by a predetermined period of time from astart of an output of another partial image information of a same frame,the another partial image information being output by another imagedisplay device corresponding to a first row of a vertical arrangement,the predetermined period being determined based on a number of the imagedisplay devices arrayed in the vertical direction and a row to which thepresent image display device belongs in the vertical arrangement.
 2. Theimage display device in accordance with claim 1, wherein: the readingprocessing unit that delays the start of the output by the predeterminedperiod which is (i−1)/(N−1) frame length based on the number N of theimage display devices arrayed in the vertical direction and the i-th rowto which the present image display device belongs in the verticalarrangement.
 3. The image display device in accordance with claim 2,wherein no delay of one frame or greater is produced between the imagedisplayed by the image display devices located in the first row and theimage displayed by the image display devices located in a third row. 4.The image display device in accordance with claim 1, wherein: for afirst vertical synchronizing signal input from an external device, thereading processing unit generates a second vertical synchronizingsignal, to which a predetermined amount of delay shift is applied basedon the number of the image display devices arrayed in the verticaldirection, and outputs the partial image information to the displaypanel at every moment based on the second vertical synchronizing signal.5. The image display device in accordance with claim 3, furthercomprising: an image information storage unit that has a memory areacapable of storing partial image information of one frame and furtherpartial image information of at least one line; and a writing processingunit that writes the partial image information of one frame in the imageinformation storage unit sequentially at every moment, based on thefirst vertical synchronizing signal.
 6. The image display device inaccordance with claim 5, wherein the writing processing unit writes thepartial image information, from image information corresponding to afirst line to the partial image information corresponding to an n-thline, within a time length from a first time to a second time, andwherein, in a next time length from the second time to a third time, thethird time being after the second time, different partial imageinformation is overwritten on the image information storage unit.
 7. Theimage display device in accordance with claim 6, wherein the writingprocessing unit overwrites the partial image information utilized to adrawing of a next image sequentially for each frame, based on the firstvertical synchronizing signal.
 8. The image display device in accordancewith claim 1, further comprising: an image information storage unit thathas a memory area capable of storing partial image information of oneframe and further partial image information of at least one line.
 9. Theimage display device in accordance with claim 8, wherein the partialimage information comprises a region allocated to the image displaydevice in the image information stored in the image information storageunit.
 10. The image display device in accordance with claim 1, whereinthe number N of the image display devices arrayed in the verticaldirection is 3 or more.
 11. The image display device in accordance withclaim 1, wherein no delay of one frame or greater is produced betweenthe image displayed by the image display devices located in the firstrow and the image displayed by the image display devices located in athird row.
 12. An image display system in which a plurality of imagedisplay devices are arrayed in a vertical direction to display one imageas a whole while an image allocated to each device is displayed via acorresponding display panel, the image display system comprising: eachof the image display devices has a reading processing unit that readsout partial image information of a frame and delays a start of an outputof the partial image information by a predetermined period of time froma start of an output of another partial image information of a sameframe, the another partial image information being output by anotherimage display device corresponding to a first row of a verticalarrangement, the predetermined period being determined based on thenumber of the image display devices arrayed in the vertical directionand a row to which the present image display device belongs in thevertical arrangement.
 13. The image display system in accordance withclaim 12, wherein the number N of the image display devices arrayed inthe vertical direction is 3 or more.
 14. An image display method inwhich a plurality of image display devices are arrayed in a verticaldirection to display one image as a whole while an image allocated toeach device is displayed via a corresponding display panel, wherein: areading processing unit provided in each of the image display devicesreads out partial image information of a frame and delays a start of anoutput of the partial image information by a predetermined period oftime from a start of an output of another partial image information of asame frame, the another partial image information being output byanother image display device corresponding to a first row of a verticalarrangement, the predetermined period being determined based on thenumber of the image display devices arrayed in the vertical directionand a row to which the present image display device belongs in thevertical arrangement.
 15. The image display method in accordance withclaim 14, wherein the number N of the image display devices arrayed inthe vertical direction is 3 or more.